1. Field of the Invention
This invention relates to heat failure of cylindrical structures. More particularly, this invention relates to a solid propellant rocket motor. Additionally, this invention relates to a solid propellant rocket motor which produces mild burning reactions rather than explosions when exposed to external fires.
2. Description of the Prior Art
Navy carrier operations especially provide the potential for aircraft fuel fires to occur in the vicinity of weapons and ordnance. Many rocket motors react after about one minute of exposure to external fires and flames. The reaction can vary from a mild burning to a violent case rupture.
Past efforts to improve the heat resisting capability of ordnance items have included placing a thermal barrier on the exterior of the rocket motor casing or warhead. By thermal insulation of the rocket motor casing or explosive, the length of time the ordnance item can be exposed to fire without reaction is increased. If the fire is not extinguished within a short period of time, the internal temperature will increase and the ordnance item may ignite and explode.
Explosion and violent rupture of a heat weakened motor can occur when the propellant grain is ignited along the central void in the grain. If combustion can be limited to the outside of the grain and properly vented, the severity of the reaction is lessened.